It is believed blue mussels are an introduced species to Australian waters. They were probably attached to the early sailing ships that traveled to Australia. Since that time, blue mussels have spread throughout the estuaries and near shore areas of Western Australia.

Blue mussels are bivalves, a shellfish with two shells. These shells protect the mussel’s soft flesh from predators such as crabs, fish - especially leatherjackets and flat worms. Blue mussels like to live on hard underwater surfaces, rocks, jetty pylons and boats.

Blue mussels are filter feeders. They get their food by pumping water through a set of gills which catch small bits of food while allowing the water to pass through. This method of eating catches algae, zooplankton and detrital material. The food is past along to the stomach where it is digested.

Being filter feeders, blue mussels readily accumulate toxins, bacteria and heavy-metals. These substances are unable to be released by the mussels and so remain in their system. It is therefore important for blue mussels to live in unpolluted water.

Blue mussels first spawn when they are about 11 months of age. At this age they are about 3cm in length. Spawning occurs in the winter months in Western Australia. It takes only one day for the fertilized egg to develop into a larvae. The larvae do not have a shell and can only move around with the ocean currents. From time to time the larvae touch on the bottom to test the surface so they may settle. If it is not right they keep looking. When they have settled and formed their shell, the mussel larvae are then called ‘spat’.

Scientific and other names
Blue mussel (Mytilus edulis)

What they look like
Blue mussels are bivalves; shellfish that have two shells surrounding their soft body. Their fan shaped shell is purplish-black on the outside and light coloured on the inside. The inner shell is smooth so that it doesn’t hurt the soft flesh of the mussel. Blue mussels grow up to 5cm in length.

Where they live
Blue mussels are found in the temperate (cooler) waters of both the northern and southern hemispheres.

Blue mussels live in marine environments on shallow, sandy bottoms, in beds or as dense masses attached to underwater structures, such as jetty pylons. Mussels are shallow water organisms, living in water below 10 metres they are most abundant at or near low tide level, where their food supply of algae is most abundant.